Method:
1. Soak the dal in water for 2 hours.
2. Grind the dal to a smooth paste adding 1 tbsp. ginger-garlic paste, one green chilli, garam masala powder, red chilli powder, salt (to taste)and a dash of water to grind.
3.Heat one tbsp. of oil in a pan and add the dal batter. Keep stirring until it becomes thick. (into the consistency of making balls).Let it cool a bit and roll small amounts of it into balls / golis.Wet your hands with water while rolling to get them smooth and round.
4.To prepare the masala, heat a tbsp. of oil in a pan and add the onion.Stir fry and add the tomato, the remaining ginger-garlic paste and green chilli.Sprinkle a pinch of turmeric and red chilli powder.Add a little water and saute for a minute.
5. Now gently place the dal golis in the masala mixture and simmer for a few minutes. Stir them carefully once or twice to coat all the masala.Garnish with coriander leaves and serve with rotis.

WITH GRAVY:
(I tried it out this way for a change.)
Grind together 2 small onions, 1 tomato, 5-6 cloves of garlic, a small piece of ginger and 1 green chilli. In a pan heat oil and saute this masala until the colour changes. Stir in salt and the dry masala powders.Put the prepared moong dal golis and simmer adding a little water to cook for 8-10 minutes. Finally stir in a few table spoons of thick coconut milk. Give 2-3 boils and garnish with chopped coriander leaves.